Rockbolt

Abstract

Device for fastening of a rockbolt (12) in a hole (11) in rock, provided with an expansion bushing (14) at the inner end. At the outer end of the rockbolt, a washer like pressure member (18) is arranged to press against the rock (19), with a nut (16). The rockbolt (12) is provided with a tube (23) extending over at least the greater part of its free length, and is provided to supply cementing grout to the inner end of the rock hole and expelling of air from the rock hole. The tube is preferably connected to transfer cementing grout through the annular passage created in the tube.

I claim: 
     
       1. Device for fastening of a rockbolt (12) in a hole (11) in rock, provided with a fastening member, particularly an expansion bushing (14) on a threaded part (13) at the inner end, and at the outer end of the rockbolt a washer like pressure member (18) to press against the rock (19), with a nut (16) on the outer threaded part (15) of the rockbolt, to press against a support element (17) with an opening for supply of cementing grout for filling the cavity between the rockbolt and the rock, to increase the fastening thereof and provide corrosion protection, wherein the rockbolt (12) is provided with a tube (23) extending over at least the greater part of its free length, said tube being provided to supply cementing grout to the inner end of the rockhole, characterized in that the support element (17) has at least a partly spherical wall defining a convex abutment against the pressure member (18) and an inner space for receiving a supply of cementing grout through a hole (27) in the wall. 
     
     
       2. Device according to claim 1, characterized in that the support element (17) is of spherical shell form and has a threaded opening (21) for the pipe (23). the pipe being provided with an outer thread at least at the outer end, and that the support member has a hole (27). which may be threaded, for introduction of cementing grout.